Field of the Invention
The present invention relates to a collation apparatus that collates an input image with a plurality of registered images, and an image searching apparatus using the collation apparatus.
Description of the Related Art
In recent years, an image searching apparatus that searches an image in which a specific object is photographed from a large amount of images has been proposed. In such an image searching apparatus, it is useful in particular to search a specific person. As one of the uses, there is a service of registering photos of faces of persons who have competed in a civil marathon beforehand, searching the registered persons from photos photographed at a plurality of points of a marathon course, and providing competitors with the photos.
Here, collation processing of face images can be utilized in a search of photos of persons, however, since illumination conditions are different respectively at individual photographing points on the course, it becomes difficult to collate faces by influence of brightness, colors, shadows or the like of the images. There is also a problem that, since photographing from the front cannot be performed depending on the photographing point, the face image photographed from an oblique direction needs to be collated. On the other hand, it may be considered to search the photos of the persons by collating something other than faces.
One method is to recognize a player number of a person, however, it is impossible to search an image in which the player number cannot be seen. Also, it may be considered to perform collation by colors or patterns of clothes, however, among the images under the different illumination conditions, the collation is affected more than the collation of faces. Considering the above, it is clear that, though the player number and clothes are used as a method of collation, it is better to be combined with a face collation processing with excellent performance.
As a system of collating faces in order to search a personal image, for example, there is a method described in On-the-fly specific person retrieval, in International Workshop on Image Analysis for Multimedia Interactive Services, by Parkhi et al. (2012). Here, image search on the Internet is utilized, a plurality of face images of celebrities are collected beforehand by inputting names, and a person is searched from video images by learning a face model of a specific person from the collected face images. However, since it is assumed to collect many face images from the Internet in the method, a search target is limited to celebrities. Also, an essential problem on a difference between a registered face photo and a condition during photographing is not solved.
An object of the present invention is to provide a collation apparatus and method capable of highly accurately collating a person even when a photographing condition or a camera installation condition is different, in an image searching apparatus that searches a specific person from a plurality of camera images, in order to solve the above-described problem.